If you didn't know better, you could make a good argument that the FAA has never heard of Christmas. That's because when your student takes a CFI checkride, he's not likely to find any Santa Claus bearing gifts. The FAA is pretty strict on these rides, and it has good reason for being so.
The CFI ride is where applicants are supposed to demonstrate their ability to teach what they know. Instead, most applicants only tell others about what they know. That's not teaching, is it?
If you want to give your applicant the best chance of passing his CFI ride, make sure he or she teaches, and doesn't just tell.
For instance, when asked to present a lesson on aerodynamics to the examiner, prepare by asking what knowledge the examiner brings to the table. Does he drive a car? Fine. Now the applicant knows that he can present aerodynamics on the basis of how a car climbs or descends a hill. Isn't preparation the first part of the teaching process?
Perhaps the applicant will explain Bernoulli's principle and demonstrate it by blowing air over a paper. Isn't explanation and demonstration the second part of the teaching process?
Next, the applicant may have the student imagine what happens when varying the angle his hand makes to air blowing from a fan. Isn't that called trial and error, the third part of the teaching process?
Finally, and perhaps most important, the applicant should pause and question the examiner about what he (as the student) has learned. This also means having the student explain some of those concepts, just to check for understanding, then evaluating his knowledge. Isn't review and evaluation the fourth part of the teaching process?